It has a lot of advantages including the duration of concentration in blood, reduction of side effects to the digestive organs and simplicity of administration to allow biologically active substances and drugs be absorbed through the skin or a mucous membrane. However, since substance permeability through the skin is low, there has been a limit to the biologically active substances and drugs capable of being transferred in a sufficient amount into a living body. Besides, it has been difficult to transfer biologically active substances having a high molecular weight and drugs through a mucous membrane.
Recently, physical acceleration methods utilizing phonophoresis and iontophoresis have been studied. Of them, iontophoresis is a method of allowing biologically active substances and drugs ionized by an electric current to be absorbed through the skin or the mucous membrane and has been studied as an administration method instead of injections. Generally, as electrodes for iontophoresis, polarization electrodes of platinum, titanium, carbon and the like and non-polarization electrodes of silver/silver chloride and the like have been employed.
However, in the case of employing these electrodes singly, it has not been possible to transfer the biologically active substances and drugs in a sufficient amount into a living body by iontophoresis.
It is the object of the present invention to provide an electrode structure which can transfer biologically active substances and drugs into a living body effectively while causing no irritation to the skin or the mucous membrane, which has been difficult according to conventional iontophoresis techniques, and also can transfer (namely, transport) biologically active substances and drugs into a living body in a sufficient amount and safety.